The present invention concerns apparatus for the winding and unwinding of continuing belt of flexible bag. Specifically, the invention contemplates one apparatus for winding continuous belt of flexible bag provided by a bag producing machine and a further device for unwinding the same continuous belt of flexible bag to be provided to a packaging machine.
The inexpensive, disposable flexible plastic bag enjoys a prominent position in the packaging industry. Typically, such bags are constructed of a variety of types of materials, with thermoplastics being the most prominent. These bags can be filled with a variety of products either in liquid, powder or solid form.
One of the benefits of this type of flexible packaging is that it can be relatively inexpensively produced in large quantities. Typically, the bags are produced on a continuous belt from a continuous sheet of bag material. Bag forming mechanisms are well known that can take the continuous sheet of bag material, fold it into a general package shape, and then seal and cut at respective locations forming the sides and tops of the package. These same bag forming machines also include the capability of adding reclosable features which permit opening and closing the bags. These reclosable features are usually in the form of interlocking male and female zipper elements.
One such type of package is shown in FIG. 1 as a continuous belt 10 of flexible packaging produced from a bag manufacturing machine in accordance with principles known to persons of skill in the art. This continuous belt 10 includes a series of consecutive packaging blanks 11, each separated by vertical slots 12. Each of the packaging blanks 11 include bonding zones 13 at the vertical slots 12 to form the sides of each of the bags. In addition, bridges 14 are provided to span across the vertical slots 12 at the lower edges of the bag to at least maintain the continuity of the bags during the bag forming and filling processes. The upper edge 15 of the continuous belt 10 is open for access at a subsequent product filling station.
In accordance with one particular type of continuous belt of packaging blanks, the belt 10 is provided with a pair of longitudinal tunnels 17, 18 on opposite sides of the open upper edge 15 of the belt. This upper edge, including the longitudinal tunnel 17, 18, can be removed from the remainder of the bag at perforations 16. A bag of this type is described more particularly in U.S. Pat. No. 4,558,556 to Jostler, which disclosure is incorporated herein by reference. As discussed in more detail in the '556 patent, along with continuation U.S. Pat. No. 4,598,421 and divisional U.S. Pat. No. 4,756,144 deriving priority therefrom, the longitudinal tunnels 17 are formed to ride along guide bars at a product filling machine. One commercial embodiment of this machine is the Joker Combi Line Packaging System sold by Joker System Aktiebolag. In accordance with this system, and again as more fully described in the '556 patent incorporated by reference, the guide bars are configured to alternatively open and close the upper edge of each of the consecutive packaging blanks 11 as the continuous belt 10 rides along the guide bar supported within the paid of longitudinal tunnels 17, 18. Further details of the filling apparatus and method can be discerned from each of the three Jostler patents.
As depicted in FIG. 4 of the Jostler '556 patent incorporated by reference, the continuous belt of packaging blanks is drawn from a horizontal stack in a magazine 21. In the case of the system depicted in these patents, the continuous belt of packaging blanks must be first provided in stacks to be housed within the magazines. In other systems, the continuous belt of packaging blanks is provided on a drum or continuous roll. A roll of this type is depicted in the patent to Collin, U.S. Pat. No. 4,260,116. A similar drum of continuous belt of packaging blanks is also shown in U.S. Pat. No. 3,751,875 to Membrino and U.S. Pat. No. 3692,251 to Melead.
Thus far in the prior art, the continuous packaging blanks are provided either vertically stacked in a magazine, such as shown in the Jostler '556 patent, or on a cylindrical drum, as described in the Collin patent. With each of these techniques, however, some difficulty arises when the upper edge of the packaging blanks includes functional features, such as the longitudinal tunnels 17 and 18 depicted in FIG. 1 of the present application. In other words, the addition of these features makes the upper edge of the continuous belt 10 thicker than the remainder of the bags, which can lead to uneven stacking and uneven dispensing on the cylindrical rolls. The present invention addresses this difficulty in a novel bag winding and pay-out system.